This invention relates to a complex switching system with memory for electronically amplified guitars, and more particularly to guitars employing humbucking coils for electromagnetic pickup from guitar strings, to permit the musician to easily select different sounds previously programmed and stored in memory in terms of at least the pickup coils to be used, the phase of the coils selected and the output level of the selected coils combined.
A humbucking guitar pickup consists of two coils wound in parallel, side by side, but with reverse magnetic polarity in order to cancel any hum, but not the actual notes of the guitar strings. The humbucking coils also color the sound. Such coloration is commonly used to advantage. In a normal electric guitar, there are provided two sets of pickup coils, a front pickup, a back pickup and a three-way selector switch which permits the musician to select either or both pickups. Also provided are independent tone control and volume control for each pickup. These controls permit the musician to color the sound for the particular type of music they are playing.
Most professional musicians have a repertoire of music of different types, so they use different guitars, one for each type, already preset. In that way time is not lost during a performance in readjusting controls for the different types of music. What is desired is a way to store all of the colorations (tonal characteristics) of the different types of music in one guitar in such a way that any particular one can be easily and quickly called out of storage. The time then lost could be less than the time the musician would need to set one guitar down and take up another.
For optimum control of tonal characteristics, the paired humbucking coils are separately controlled through selection switches, with the phase of a coil selected either inverted or not. With two pickups, for example, there are four coils which provide a total of fifteen combinations of just coil selection. When one also provides for separate phase control of each coil selected, there are theoretically 64 possible combinations, although some are redundant in the sense that they produce the same net effect as others, so that in actuality there may only be 59 useful combinations. But then upon combining the pickup of selected and phased coils, there is also a need to adjust the volume since a given combination may provide more input signal amplitude to the power amplifier than another, and beyond that, there may be different volume selections to be made. To incorporate all of the possible combinations requires of the musician such complex switching combinations that it is practically impossible for him to do so during a performance as he goes from one song or number to another. Thus, what is required is a memory to prestore all of the desired combinations for electronic recall with a minimum of addressing operations for the musician to remember and perform.